Line printer and coordinated line feed means



Nov. 12, 1968 H. F. BURKHARD 3,410,204

LINE PRINTER AND COORDINATE!) LINE FEED MEANS Filed Oct. 21, 1966 2 Sheets-Sheet 1 FIG.|

INVENTOR,

HENRY F. BURKHARD Nov. 12, 1968 H. F. BURKHARD 3,410,294

LINE PRINTER AND COOHDINATED LINE FEED MEANS 2 Sheets-Sheet 2 ,II \\\n YEI I2 25 PRINTING 8- CONTROL 65 43 SIGNAL GENERATOR Filed 00 21, 1966 FIG. 2

SELECTOR LOGIC FIG. 4

INPUT D E E rr. E N L m L AM N R G E l N S E G INVENTOR, HENRY F. BURKHARD ATTORNEYS United States Patent 3,410,204 LINE PRINTER AND (ZOORDINATED LINE FEED MEANS Henry F. Burkhard, Eatontown, N.J., assignor to the United States of America as represented by the Secretary of the Army Filed Oct. 21, 1966, Ser. No. 588,639 3 Claims. (Cl. 101-93) ABSTRACT OF THE DISCLOSURE A printer is provided with print heads which are capable of printing on a print receiving medium during the line feed operation. A first group of print heads, at the beginning of the line, are moved from the normal printing location down one line width so that these print heads will be in position to start printing the next line. During the line feed operation, a sprocket mechanism will line feed both the medium and the first group of print heads in unison up to the normal printing location. As the medium and the heads are being fed, however, printing may take place since the heads and medium are at a zero relative velocity and the heads are properly aligned with the medium.

The present invention relates to high speed printers, and more particularly to an improved printer capable of printing at a high constant rate which is not interrupted during line feed operations.

Those concerned with the development of high rate telegraphs, computers, data processors, etc., have recognized the need for increasing substantially the speed of present day high speed printers. However, one of the problems confronting designers of high speed printers has been the elimination of the time delays introduced as a result of the line feed operation. Such time delays result in either the loss of some information or the necessity of providing a storage means for storing the information received during the line feed period. The present invention overcomes these ditliculties by providing a printing device which has means for printing during the line feed periods.

The exact nature of this invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawing in which:

FIGURE 1 is a perspective view of the invention;

FIGURES 2 and 3 represent side views, partly in section, of the invention as shown in FIGURE 1; and

FIGURE 4 is a block diagram of the electronic controls for the invention of FIGURES 1-3.

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views, there is shown a printer contained in a housing 11 having an entrance slot 12 and an exit slot 13 for a sheet of paper 14 which is fed past the printer 10 by a feed mechanism 15.

Feed mechanism 15 comprises a drive roller 16 having sprockets 17 thereon, and an idler roller 18. A paper feed tractor 19, which includes an endless flexible belt 20 having sprockets 21 and openings 22 located at the edges thereof, extends around rollers 16 and 18. Sprockets 17 on roller 16 communicate with openings 22 to drive tractor 19. Roller 16 is driven by a motor 70', FIGURE 4, attached to drive shaft 23. Idler roller 18 is mounted on shaft 24 to freely rotate under the influence of tractor 19 which is in frictional contact therewith.

A sheet of paper 14 having perforations 26 at the edges thereof extends from the fanfold through slot Patented Nov. 12, 1968 12 to the interior of housing 11 where it passes over tractor 19 with sprockets 21 extending through slots 26. The paper 14 then passes through slot 13 to the exterior of housing 11.

The printer 10 comprises moveable printing heads 30 and stationary printing heads 31 which are mounted on an axle in juxtaposition to the paper 14. Heads 30 are free to rotate about axle 32 and each head 30 has a depending printing head lifter arm 33. Printing heads 30 and 31 may take any of the well known froms which print on either a mechanical, thermal, optical, or electrical principle. An example of a suitable thermal printing head may be found in US. Patent 3,161,457.

The dashed lines in FIGURE 1 extending from heads 30 to heads 31 indicate that the heads, either moveable or stationary, located in these locations have been omitted to simplify the illustration.

A control mechanism for controlling the position of moveable printing heads 30 includes a series of release magnets 40 and a litter bar 41 mounted on a pedestal 42. Release magnets 40 comprise a U-shaped portion having a coil 43 wound thereon and a pivoted stud 44 connected to the U-shaped portion by a spring 45 which normally biases the stud 44 to a position just under arm 33 (see FIGURE 3). In this position the printing heads are held by stud 44 in the normal printing position and are aligned with stationary heads 31. However, upon energization of magnet 40, stud 44 is moved out from under arm 33 and the associated head 30 will rotate about axle 32 until arm 33 rests on bar 41, which is normally biased down upon pedestal 42 by springs 46 to the position shown in FIGURE 3. Bar 41 is guided for free movement in the vertical direction by a triangular shaft 48 which is free to ride in vertical slots 47. The triangular shaft and the slot cooperate to permit rotation of bar 41 in the counterclockwise direction as seen in FIGURES 2 and 3. However, rotation in the clockwise direction by bar 41 is prevented past the position shown in FIGURES 2 and 3. Bar 41 also includes a nose portion 49 which protrudes past pedestal 42 into the path of movement of sprockets 21. Sprockets 21 will lift bar 41 off pedestal 42 when the paper 14 is being fed. When bar 41 has reached the uppermost position, coil 43 will be deenergized, stud 44 will be released and move to the position just under arm 33, and a solenoid 50 mounted on housing 11 will be energized to move armature 51 into contact with bar 4 1 to rotate the bar 41, thereby stripping nose 49 off sprockets 21 and permitting springs 46 to force bar 41 down onto pedestal 42.

The sequence of operations of the printer and the movements of the various controls may be best understood with references to FIGURES 2, 3, and 4. The input line would usually contain the printing information and the control instructions such as line feed. This information may be in coded form. A logic circuit 61 will process the input signal and determine if it is a printing signal or a control signal. If the input signal is a printing signal, it will be fed to generator 62 via line 63 where the proper printing head 30 or 31 will be energized via one of the lines contained in cable 64. Generator 62 will also generate a control signal to operate magnets 40 by energizing one of the coils 43 via cable 65 which passes through a reset switching device 71. The printing heads are normally in the position shown in FIGURE 3 when the printing signal is transmitted to the heads 30 and 31 by generator 62. After a head 30 performs its particular printing operation, the corresponding coil 43 will be en ergized permitting the head to be released and fall to a position where arm 33 rests on bar 41. The heads 30 will remain in this position until a line feed operation is initated. A line feed operation will be initiated by either generator 62 via line 67 when the last head 31 has been operated (end of line), or by an input signal via line 66 when a Line Feed" signal has been received at the input 60. Line feed signal generator 68 will then energize motor 70 via line 69. Motor 70 will rotate roller 16 which will drive tractor 19 to lift both the paper 14 and bar 41 via sprockets 21. Now, as paper 14 is being fed, heads 30 will be moving up to the normal printing position as shown in FIGURE 3. However, since the printing heads and the paper are both moving in unison during this line feed operation, printing may continue during this period. Therefore, because printing is now possible during the line feed operation, generator 62 may continue to transmit printing information over line 64 without any loss of information or storage requirement. The number of move able heads 30 which are employed will depend on the length of time required to complete the line feed operation and the rate at which information is being received over line 60.

After the line feed operation is completed, the motor 70 will generate a reset signal over line 7'2 to energize the reset switch 71, thereby deenergizing all coils 43 and releasing studs 44. A signal is also fed to solenoid 50 when motor '70 has completed its rotation, thereby energizing the solenoid 50 and moving armature 51 (see FIGURE 2) into contact with bar 41 to rotate the latter out of engagement with sprockets 21. It is again pointed out that during the line feed operation printing information may continue to be fed to the printing heads over cable 64 without any interruption.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings.

It is noted, for example, that the moveable printing heads 30 may be designed to move along a more complex path than the simple are shown in the drawing. It would, of course, be desirable to provide a motion for the moveable printing heads 30 which would eliminate any relative motion between the paper and the heads during the line feed operation. For example, in the disclosed embodiment a vertical translational motion of heads 30 would produce less relative movement between the heads 30 and the paper 14 during the line feed operation than would the simple rotational motion which is shown merely for purposes of illustration. Of course, in machines using other modes of printing even more complex movements of the printing elements and the feed mechanisms would be required. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A printer comprising; a plurality of print heads linearly disposed at a first printing station; a print receiving medium; energizable printing means operably associated with each said print head to cause said print heads to print selective characters on said medium; means responsive to the operation of each said printing means for moving a predetermined fixed group of said print heads to a second printing station upon energization of said printing means; feed means for intermittently feeding said medium and for moving simultaneously said print heads at said second station back to said first station while feeding said medium at substantially the same linear speed in the direction of feed of said medium; and said predetermined fixed group of print heads being in printing relationship with said medium during said movement.

2. A printer comprising; a plurality of printing means for printing in succession a plurality of selective characters in a line on a print receiving medium, feed means for feeding said medium in a step by step fashion past said printing means in a direction substantially perpendicular to said line to form a plurality of successive parallel lines of print on said medium; means associated with each said printing means of a group of said printing means located at the beginning of said line, for moving the associated printing means from the original printing position through a distance of one of said line widths in a direction opposite to the direction of feed for said medium; and means responsive to said feed means for moving the printing means of said group back to the said original printing position with substantially zero relative speed between said medium and said printing means in the direction of feed of said medium.

3. A printer comprising; a plurality of print heads, each said head having means for printing selective characters on a print receiving medium; said print heads mounted side by side along a first line, a feed tractor mounted adjacent said print heads for movement in a first direction perpendicular to the line of said print heads; means on said tractor for engaging a print receiving medium; input means for energizing said print heads in succession from one end to the other end of said line of said print heads; a first group of said print heads at said one end being moveable out of said first line to a second line parallel to said first line, means associated with each said print head of said first group for moving said associated print head from said first line to said second line upon energization of said print head by said input means; and drive means for moving said feed tractor and said print heads of said first group into said first line with substantially zero relative speed in said first direction.

References Cited UNITED STATES PATENTS 196,025 10/1877 Kurtzmann t 101-92 1,506,242 8/ 1924 Keller 10192 1,896,538 2/1933 Bryce t 101--93 2,915,966 12/1959 Jacoby 10193 2,915,967 12/1959 Gehring et al. 101-93 2,935,016 5/1960 Miller 101-93 3,128,694 4/1964 Kittler 10193 3,139,820 7/1964 Kittler 101--93 3,228,325 1/ 1966 Miller 10193 3,309,989 3/ 1967 Solheim et al. 101---93 WILLIAM B. PENN, Primary Examiner. 

